A Colaba-based businessman, suspected to be henchman of underworld don Dawood Ibrahim [Images], handed over arms and explosives to the Lashkar e Tayiba terrorists for carrying out the attacks on Mumbai, in what is emerging as the first major joint operation by the Karachi-based gangster and the banned outfit, official sources said in Mumbai.

Ajmal Amin, the only terrorist arrested during the operation, told interrogators that the dozen ultras who sailed from Karachi had come to Sassoon Dock from where they were taken first to Cuff Parade and later to the Gateway of India in boats arranged by a frontman of Dawood, who runs several custom clearing houses in Mumbai, the sources claimed.

The Mumbai police and central security agencies have launched a massive manhunt for the businessman considered to be a henchman of Dawood, who has been listed as a global terrorist having links to the Al Qaeda [Images] by the United States.

The suspect looks after some customs clearing mechanism and also indulges in diesel smuggling for the underworld don, the sources claimed.

After getting into waiting boats arranged by Dawood's gang in Mumbai, arms, ammunition and plastic explosives were quickly transferred to the waiting boats that took the terrorists to the Gateway of India which was had been marked as the launching pad for the terror strike, the first of its kind in the country's terrorism history.

The intelligence agencies had sent a warning note to the Coast Guard to keep a watch out for an unidentified Pakistani trawler sailing from Karachi port which may enter into Indian waters. While the Coast Guard was looking for a Pakistani or unidentified vessel, the terrorists hijacked the Indian fishing trawler Kuber after killing its crew and entered the Mumbai seas.

The Coast Guard captured the abandoned vessel, which had a global positioning system on board, as it was drifting nearly four nautical miles off the coast of Mumbai on Thursday morning, several hours after the terrorists struck.

The terrorist claimed during his interrogation that they had even planned to leave Mumbai back for Karachi, if luck favoured them, the sources said.

This solves the mystery of the GPS instrument on the Kuber which had been fed with a return map to Karachi, the sources said.

The underworld don's men had also provided a complete pictures of the two hotels and the Chabad/Nariman House, which houses the a Jewish centre.

Meanwhile, investigators were going through the call data details downloaded from the satellite phone recovered from the abandoned trawler.

It revealed numbers that have been traced back to the LeT's 'chief of operations', Muzamil.

The terrorists had been in constant touch with their masters across the border and some of the communications have been intercepted by both the army as well as the elite National Security Guards.

The terrorist said Taj Mahal [Images] and Trident-Oberoi were selected because the two hotels have a large clientele of Britishers and US citizens; besides that, a large number of Israeli businessmen had come to the Trident for attending a diamond exhibition, the sources said

The terrorists were also asked by their "masters" to engage security personnel in negotiation besides throwing grenades.

The two terrorists holed up in Nariman House had made attempts to hold talks on two occasions, the sources said.